/**
 * Software License, Version 1.0
 * 
 * Copyright 2003 The Trustees of Indiana University.  All rights reserved.
 * 
 *
 *Redistribution and use in source and binary forms, with or without 
 *modification, are permitted provided that the following conditions are met:
 *
 *1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license;
 *2) All redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the disclaimer listed in this license in
 * the documentation and/or other materials provided with the distribution;
 *3) Any documentation included with all redistributions must include the 
 * following acknowledgement:
 *
 *"This product includes software developed by the Community Grids Lab. For 
 * further information contact the Community Grids Lab at 
 * http://communitygrids.iu.edu/."
 *
 * Alternatively, this acknowledgement may appear in the software itself, and 
 * wherever such third-party acknowledgments normally appear.
 * 
 *4) The name Indiana University or Community Grids Lab or NaradaBrokering, 
 * shall not be used to endorse or promote products derived from this software 
 * without prior written permission from Indiana University.  For written 
 * permission, please contact the Advanced Research and Technology Institute 
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202.
 *5) Products derived from this software may not be called NaradaBrokering, 
 * nor may Indiana University or Community Grids Lab or NaradaBrokering appear
 * in their name, without prior written permission of ARTI.
 * 
 *
 * Indiana University provides no reassurances that the source code provided 
 * does not infringe the patent or any other intellectual property rights of 
 * any other entity.  Indiana University disclaims any liability to any 
 * recipient for claims brought by any other entity based on infringement of 
 * intellectual property rights or otherwise.  
 *
 *LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO 
 *WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 *NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF 
 *INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS. 
 *INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS", 
 *"VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.  
 *LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR 
 *ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION 
 *GENERATED USING SOFTWARE.
 */
package cgl.narada.util;

import java.security.MessageDigest;
import java.security.SecureRandom;

import org.doomdark.uuid.UUID;
import org.doomdark.uuid.UUIDGenerator;

/** This class provides a small wrapper around the JUG UUIDGenerator written
    by Tatu Saloranta, tatu.saloranta@iki.fi.
    
    This class just adds a couple of things such as abstract the namespace
    UUID generation from the applications that need to generate uuids.
    
    @author Shrideep Pallickara
    $Date$
    $Revison$
*/


public final class UUIDRetriever {
  public static final UUIDRetriever retriever = new UUIDRetriever();
  private static UUIDGenerator uuidGenerator;
  private static UUID nameSpaceUUID;
  private static MessageDigest digest;
  private static String uuidBaseName;
  private static SecureRandom secureRandom;
  private static String moduleName = "UUIDRetriever: ";

  private UUIDRetriever(){
    try {
      digest = MessageDigest.getInstance("SHA");
      
      uuidGenerator = UUIDGenerator.getInstance();
      uuidBaseName = "www.naradabrokering.org";
      nameSpaceUUID = 
	uuidGenerator.generateNameBasedUUID(null, uuidBaseName, digest);
      secureRandom = new SecureRandom();
    } catch (Exception ex) {
      System.out.println(ex);
    }
  }
  
  public static UUIDRetriever getInstance() {
    return retriever;
  }

  private UUID getNameSpaceUUID() {
    return nameSpaceUUID;
  }

  public UUID generateNameBasedUUID() {
    UUID uuid = uuidGenerator.generateNameBasedUUID(nameSpaceUUID, 
						    uuidBaseName, digest);
    return uuid;
  }
  
  public UUID generateTimeBasedUUID() {
    UUID uuid = uuidGenerator.generateTimeBasedUUID();
    return uuid;
  }
  
  public UUID generateRandomBasedUUID() {
    UUID uuid = uuidGenerator.generateRandomBasedUUID(secureRandom);
    return uuid;
  }

  public String getNameBasedUUIDAsString() {
    UUID uuid = generateNameBasedUUID();
    return uuid.toString();
  }
  
  
  public String getTimeBasedUUIDAsString() {
    UUID uuid = generateTimeBasedUUID();
    return uuid.toString();
  }

  public String getRandomBasedUUIDAsString() {
    UUID uuid = generateRandomBasedUUID();
    return uuid.toString();
  }
  

  public static void main(String[] args) {
    UUIDRetriever retriever = UUIDRetriever.getInstance();
    for (int i=0; i<15; i++) {
      System.out.println(retriever.getRandomBasedUUIDAsString());
    }
  }

}
